Dictionary:

gorp

  (gôrp)

A mixture of high-energy foods, such as nuts and dried fruit, eaten as a snack.

[Origin unknown.]

Eaten as a snack, this dry mixture consists of a combination of foods, usually nuts, seeds, raisins or other dried fruit and oats. It's particularly favored by hikers and campers as an energy booster.

[CMU: perhaps from the canonical hiker's food, Good Old Raisins and Peanuts] Another metasyntactic variable, like foo and bar.